基于磁悬浮密度计的高精度流体PVT测量系统

High accuracy fluid PVT measurement system based on magnetic suspension densimeter

建立了一套基于磁悬浮密度计的流体PV T 测量系统，其温度测量范围203.15～423.15 K ，标准不确定度为0.005 K ，压力测量范围0～7 M Pa ，标准不确定度为700 Pa ．通过对恒温系统的改进，缩短了实验本体达到热平衡的时间，提高了温度稳定性．利用该系统对高纯氮气在271～345 K ，0～6 MPa范围内进行了密度测量，实验结果与NIST REFPROP9.0数据相比偏差在0.1％以内，并对由于拟合维里方程的不确定度、温度测量和压力测量不确定度引起的密度结果的不确定进行了分析．

A fluid PVT measurement system based on magnetic suspension densimeter was developed .The temperature range is 203.15~423.15 K with standard uncertainty of 0.005 K ,and the pressure range is 0-7.0 MPa with standard uncertainty of 700 Pa .The temperature control system was modified ,thus the time reaching equilibrium state was shortened and the temperature stability was improved .The developed PVT system was used to measure the density of high purity nitrogen at 271-345 K ,0-6 MPa ,and the average absolute deviation between experimental results and the NIST REFPROP 9.0 data was within 0.1% ,and the density uncertainties due to the uncertainties of fitted virial equation and measured temperature and pressure was analyzed .